A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
This detailed and engaging lesson focuses on the importance of the excretion of carbon dioxide and urea in humans. It also looks at how the urea is formed as a result of deamination in the liver and as such covers the Core and Supplement content of the early section of topic 13 of the CIE IGCSE Biology specification.
The lesson begins with a “Crack the code” type task which will enable the students to learn the meaning of excretion and specifically how it relates to the products of metabolism. Excretion is often confused with egestion by students so this misconception is addressed immediately and as a result they will understand that carbon dioxide and urea have to be excreted whereas faeces is egested. Moving forwards, time is taken to explain why carbon dioxide needs to be excreted and links are made to the earlier topic of enzymes and how a fall in pH could affect their activity. The rest of the lesson focuses on the formation of urea in the liver. Whilst learning about deamination, students will also be introduced to the process of assimilation and the production of rge plasma protein fibrinogen is used to explain the importance of this function of the liver. In addition to understanding checks and prior knowledge checks, quiz competitions are included in the lesson to introduce key terms in a fun and memorable way.
This lesson has been designed for students studying the CIE IGCSE Biology course but is also suitable for older students who are starting the topic of excretion or the functions of the liver and want to recall the key facts.
This lesson describes the non-specific responses of the body to infection which include inflammation, lysozyme action, interferon and phagocytosis. The detailed PowerPoint and accompanying resources have been primarily designed to cover the content of point 6.8 of the Edexcel International A-level Biology specification but key details such as antigen-presentation are also introduced to prepare students for upcoming lessons on the immune response (6.9 & 6.10).
At the start of the lesson, the students are challenged to recall that cytosis is a suffix associated with transport mechanisms and this introduces phagocytosis as a form of endocytosis which takes in pathogens and foreign particles. This emphasis on key terminology runs throughout the course of the lesson and students are encouraged to consider how the start or end of a word can be used to determine meaning. The process of phagocytosis is then split into 5 key steps and time is taken to discuss the role of opsonins as well as the fusion of lysosomes and the release of lysozymes. A series of application questions are used to challenge the students on their ability to make links to related topics including an understanding of how the hydrolysis of the peptidoglycan wall of a bacteria results in lysis. Students will be able to distinguish between neutrophils and monocytes from a diagram and at this point, the role of macrophages and dendritic cells as antigen-presenting cells is described so that it can be used in the next lesson. The importance of cell signalling for an effective immune response is discussed and the rest of the lesson focuses on the release of two chemicals - interferons and histamine. During the interferon section, references are made to a previous lesson on HIV structure and action so students can understand how the release of these signalling proteins helps neighbouring cells to heighten their anti-viral defences. A step by step guide is used to describe the release of histamine in the inflammatory response and the final task challenges students to use this support to form a detailed answer regarding the steps in inflammation.
This detailed lesson describes the transport of sodium and potassium ions in the maintenance of resting potential and how an action potential is formed. The engaging PowerPoint and accompanying resources have been designed to cover the detail included in points 9.5 (i) & (ii) of the Edexcel A-level Biology B specification.
This topic is commonly assessed in the terminal exams so a lot of time has been taken to design this resource to include a wide range of activities that motivate the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs.
Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells.
This detailed lesson outlines the characteristics features of the kingdoms Protoctista, Fungi, Plantae and Animalia. The engaging PowerPoint and accompanying resources have been designed to cover point 18.2 [c] of the CIE International A-level Biology specification which states that students should be able to describe the features of these four eukaryotic kingdoms.
This lesson begins with a knowledge recall as students have to recognise that prior to 1990, kingdom was the highest taxa in the classification hierarchy. Moving forwards, they will recall the names of the five kingdoms and immediately be challenged to split them so that the prokaryotae kingdom is left on its own. The features of this kingdom are given so that the lesson can focus on the four eukaryotic kingdoms. Students are constantly challenged on their understanding of the current topic as well as that of earlier topics, as demonstrated by a differentiated task about the structure and function of cellulose which was covered in topic 2. This task is found in the section of the lesson where the main constituent of the wall can be used to distinguish between plantae, fungi and prokaryotae. Quick quiz competitions, such as SAY WHAT YOU SEE are used to introduce key terms in a fun and memorable way. The final part of the lesson looks at the protoctista kingdom and students will come to understand how these organisms tend to share a lot of animal or plant-like features.
Students commonly confuse the two forms of cell division, so this revision lesson has been designed to address those mistakes and misconceptions. The PowerPoint and accompanying resources have been planned to challenge the students on their understanding of the details of points 1.2.1, 1.2.2 and 6.1.2 of the AQA GCSE biology and combined science specifications.
The lesson goes through each of the three stages of the cell cycle including mitosis, to ensure that students can describe the key events and state the outcome in terms of the daughter cells. The lesson contains a series of tasks which include exam questions, discussions and a quiz which allow the students to assess their understanding. The final part of the lesson focuses on meiosis and specifically the differences to mitosis in terms of the number of cell divisions, the gametes formed, and their genetic make up.
This lesson has been designed to be used for revision purposes in the lead up to the GCSE exams or in preparation for an end of topic test or mocks.
This fully-resourced lesson describes the ultrastructure of eukaryotic cells and the role of the RER and Golgi apparatus in protein transport. The engaging and detailed PowerPoint and accompanying exam-question worksheets (which are all differentiated) have been primarily designed to cover point 3.2 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but also covers 3.1 which states that students should know that living organisms are made of cells, sharing some common features
As cells are the building blocks of living organisms, it makes sense that they would be heavily involved in all of the 8 topics in the Edexcel course and intricate planning has ensured that these links to previously covered topics as well as upcoming ones are made throughout the lesson. A wide range of activities, that include exam-style questions, class discussion points and quick quiz competitions, will maintain motivation and engagement whilst covering the finer details of the following structures:
nucleus
nucleolus
centrioles
ribosomes
rough endoplasmic reticulum
Golgi apparatus
lysosomes
smooth endoplasmic reticulum
mitochondria
cell surface membrane
As mentioned above, all of the worksheets have been differentiated to support students of differing abilities whilst maintaining challenge
Due to the detail that is included in this lesson, it is estimated that it will take in excess of 3 hours of allocated A-level teaching time to go through all of the tasks
This revision resource has been designed with the simple aim of motivating the students whilst they assess their understanding of the content found in module 2.1.6 (Cell division, cell diversity and cellular organisation) of the OCR A-level Biology A specification. The resource includes a detailed and engaging Powerpoint (75 slides) and an associated worksheet, which has been differentiated to allow students of differing abilities to access that task.
The range of activities have been designed to cover as much of the content as possible but the following sub-topics have been given particular attention:
The main stages of mitosis
The cell cycle including the stages of interphase and cytokinesis
The significance of meiosis in terms of variation
The main stages of meiosis
How the cells of animals are specialised to perform particular functions
The features of squamous and ciliated epithelium
How the cells of plants are specialised to perform particular functions
In addition to these topics, some topics from other modules such as organelles and magnification are tested in order to challenge the students on their ability to make links between the modules. The range of activities include exam questions and understanding checks as well as quiz competitions to maintain student engagement.
This lesson describes the ecological, economic and aesthetic reasons for maintaining biodiversity. The PowerPoint and accompanying resources are filled with real-life biological examples and have been designed to cover point 4.2.1 (g) of the OCR A-level Biology A specification.
Many hours of research have gone into the planning of the lesson so that interesting examples are included to increase the relevance of the multitude of reasons to maintain biodiversity. These include the gray wolves and beavers of Yellowstone National Park and the Za boabab in the Madagascar rainforests as examples of keystone species. Students will learn that these species have a disproportionate effect on their environment relative to their abundance and exam-style questions and guided discussion periods are used to challenge them to explain their effect on other species in the habitat. The OCR exams have a heavy mathematical content and this is reflected in this lesson as students are challenged to complete a range of calculations to manipulate data to support their biological-based answers. All of the exam questions that are included throughout the lesson have mark schemes embedded into the PowerPoint to allow the students to assess their progress. Moving fowards, the economic ans aesthetic reasons to maintain biodiversity are considered, and there is a focus on the soil depletion that occurs when a continuous monoculture is used. The 1 Billion tree scheme that began in New Zealand in 2018 is introduced and the reasons that some groups of people are objecting to what they consider to be a pine monoculture are discussed. Students will recognise that the clear felling of the trees dramatically changes the landscape and that the increased runoff that results can have catastrophic affects for both aquatic life and for humans with floods.
A number of quiz competitions are included in the lesson to introduce key terms in a fun and memorable way and some of the worksheets have been differentiated to allow students of differing abilities to access the work
This fully-resourced lesson describes the development of the humoral and cell-mediated immune responses. The detailed PowerPoint and accompanying resources have been designed to cover points 6.7 (ii) & (iii) as detailed in the Edexcel A-level Biology B specification and includes descriptions of the roles of antigen-presenting cells, T helper cells, cytokines, T killer cells, B cells, clonal selection and plasma cells.
Antigen presentation was introduced at the end of the previous lesson so the task at the start of this lesson challenges students to recognise the name of this process and then they have to spot the errors in the passage that describes the details of this event. This reminds them that contact between the APC and T lymphocytes is necessary to elicit a response which they will come to recognise as the cell-mediated response. A series of quick quiz rounds reveals key terms in a memorable way and one that is introduced is helper T cells. Time is then taken to describe the importance of cell signalling for an effective response and students will learn how the release of chemicals by these cells activates other aspects of the response. The role of the killer T cells and their production of cytotoxins is also described before an exam-style question is used to check on their understanding at this point of the lesson. This leads into the section of the lesson that deals with the humoral response and students will understand how this involves the antibodies that are produced by the plasma cells that are the result of clonal selection and expansion. The T and B memory cells are also introduced so that students can understand how they are retained in the body even after the pathogen has been overcome and will play a critical role in the development of immunity. This prepares the students for the next lesson about the role of these memory cells in the secondary immune response.
This lesson describes how the expression of a gene mutation impairs the functioning of the organ systems in people with cystic fibrosis. The detailed PowerPoint and accompanying worksheets have primarily been designed to cover point 2.16 in AS unit 1 of the Edexcel International A-level Biology specification but also challenge the students on their knowledge of previously-covered topics such as inheritance, protein synthesis and the genetic code as well as making links to the upcoming topics of loci and post-transcriptional changes.
The main focus of the lesson is the CFTR gene and the functions of the ion channel that is synthesised when this gene is expressed. As well as explaining that this channel allows chloride ions to flow across the apical membrane of the epithelial cells, time is taken to emphasise the importance of its inhibition on the ENaC, which prevents the flow of sodium ions back into the cells. A step by step guide is then used to describe the sequence of events that result in mucus which is motile and can be moved by the wafting action of the cilia in healthy individuals. This leads into the section of the lesson which considers the inheritance of cystic fibrosis in an autosomal recessive manner and then focuses on the change in the primary structure of the channel which results from one of over 1500 different gene mutations. Again, the students are guided through the events that lead to the depletion of the apical surface liquid and the cilia being unable to move the viscous mucus. Although the majority of the lesson is described with reference to the gaseous exchange system, the impaired functioning of the digestive system in terms of the blockage of the pancreas and liver secretions is considered and discussed and the students are challenged on their understanding through a range of exam-style questions.
All of the questions included in the lesson have mark schemes which are embedded into the PowerPoint and this allows the students to assess their progress.
Due to the detailed content of this lesson, it is estimated that it will take in excess of 3 hours of allocated A-level teaching time to cover
This lesson describes how the hydrolysis of ATP provides energy for biological processes such as active transport and endocytosis and exocytosis. The PowerPoint and accompanying resources have been designed to cover points 4.2 (iv), (v) & (vi) of the Edexcel A-level Biology B specification
The start of the lesson focuses on the structure of this energy currency and challenges the students to use their knowledge of nucleotides and specifically RNA nucleotides to recognise the components of ATP. As a result, they will learn that this molecule consists of adenine, ribose and three phosphate groups. In order to release the stored energy, ATP must be broken down and students will be given time to discuss which reaction will be involved as well as the products of this reaction. Time is taken to describe how the hydrolysis of ATP can be coupled to energy-requiring reactions and this leads into a series of exam-style questions where students are challenged on their knowledge of simple and facilitated diffusion to recognise that ATP is needed for active transport. These questions also challenge them to compare active transport against the forms of passive transport and to use data from a bar chart to support this form of transport. In answering these questions they will discover that carrier proteins are specific to certain molecules and time is taken to look at the exact mechanism of these transmembrane proteins. A quick quiz round introduces endocytosis and the students will see how vesicles are involved along with the energy source of ATP to move large substances in or out of the cell. The lesson concludes with a link to a future topic as the students are shown how exocytosis is involved in a synapse and in the release of ADH from the pituitary gland during osmoregulation.
This lesson looks at the structure of the DNA that is found in the nucleus, mitochondria and chloroplasts of eukaryotic cells and in prokaryotic cells. Both the engaging PowerPoint and accompanying resources have been designed to cover the first part of point 4.1 of the AQA A-level Biology specification.
As students will already have some knowledge of this nucleic acid from GCSE and from the earlier A-level topics, the lesson has been written to build on this prior knowledge and then to add key detail. As well as focusing on the differences between the DNA found in these two types of cells which includes the length, shape and association with histones, the various tasks will ensure that students are confident to describe how this double-stranded polynucleotide is held together by hydrogen and phosphodiester bonds. These tasks include exam-style questions which challenge the application of knowledge as well as a few quiz competitions to maintain engagement.
This detailed and fully-resourced lesson describes the structure and properties of the cell membrane, focusing on the phospholipid bilayer and membrane proteins. The PowerPoint and accompanying worksheets have been designed to cover point 2.2 of the Pearson Edexcel A-level Biology A specification and makes links to the fluid mosaic model which is covered in greater detail in the next lesson.
Students were introduced to triglycerides in topic 1 and the start of this lesson challenges them to recall the structure of this lipid to identify the shared features of a phospholipid. This introduces the structure of this macromolecule as a glycerol molecule, two fatty acids and a phosphate group. Time is taken to look at the differing properties of the phosphate group and the fatty acid tails so that students become comfortable with the terms hydrophobic and hydrophilic. At this point, the class is given an opportunity to discuss how the phospholipids are arranged when both the inside and outside of the cell contains an aqueous solution and the phospholipid bilayer as the fabric of the membrane is subsequently met. In a link to some upcoming lessons on the transport mechanisms, the students will learn that only small, non-polar molecules can move by simple diffusion through the tails of the bilayer. This introduces the need for transmembrane proteins to allow large or polar molecules to move into the cell by facilitated diffusion and active transport. It is at this point of the lesson that students will meet the fluid mosaic model and will begin to understand how this describes the dynamic nature of the membrane as well as explaining the interaction with the environment. Moving forwards, the structure of cholesterol is covered and students will learn that this hydrophobic molecule sits in the middle of the tails and therefore acts to regulate membrane fluidity. The final part of the lesson challenges the students to apply their newly-acquired knowledge to a series of questions where they have to explain why proteins may have moved when two cells are used and to suggest why there is a larger proportion of these proteins in the inner mitochondrial membrane than the outer membrane.
This lesson describes the role of the rER and the Golgi apparatus in the formation of proteins, the transport within cells and their secretion. The PowerPoint and accompanying resources have been designed to cover point 3.4 of the Edexcel International A-level Biology specification and also includes key details about the role of the cytoskeleton in the transport of the vesicles that contain the protein between the organelles and the membrane.
The lesson begins with the introduction of the cytoskeleton and explains how this network of protein structures transverses across the cytoplasm and is fundamental to the transport of molecules between organelles. The lesson has been planned to closely tie in with the previous lesson on the ultrastructure of eukaryotic cells and students are challenged on their knowledge of the function of the organelles involved in protein formation (and modification) through a series of exam-style questions. By comparing their answers against the mark scheme embedded in the PowerPoint, students will be able to assess their understanding of the following:
Transcription in the nucleus to form an mRNA strand and the exit of this nucleic acid through the nuclear pore
Translation at the ribosomes on the surface of the rER to assemble the protein
Transport of the vesicles containing the protein to the Golgi apparatus
Modification of the protein at the Golgi apparatus
Formation of the Golgi vesicle and its transport to the cell membrane for exocytosis
Time is taken to discuss the finer details of this process such as the arrival of the vesicle at the cis face and the transport away from the trans face and the requirement of ATP for the transport of the vesicles along the microtubule track and exocytosis.
The remainder of the lesson uses a series of exam-style questions about digestive enzymes (extracellular proteins) to challenge the students on their recall of the structure of starch and proteins
This engaging lesson describes the structure, properties and functions of the monosaccharides, disaccharides and polysaccharides. The PowerPoint lesson has been designed to cover point [c] as detailed in AS unit 1, topic 1 of the WJEC A-level Biology specification and it makes clear links to the upcoming lessons in this topic on alpha and beta glucose and the properties of starch, glycogen, cellulose and chitin.
The lesson begins with a made-up round of the quiz show POINTLESS, where students have to try to identify four answers to do with carbohydrates. In doing so, they will learn or recall that these molecules are made from carbon, hydrogen and oxygen, that they are a source of energy which can sometimes be rightly or wrongly associated with obesity and that the names of the three main groups is derived from the Greek word sakkharon. A number of quick quiz rounds have been written into the lesson to introduce key terms in a fun and memorable way and the first round allows the students to meet some of common monosaccharides. Moving forwards, students will learn that a disaccharide is formed when two of these monomers are joined together and they are then challenged on their knowledge of condensation reactions which were originally encountered during the lesson on water. Students will understand how multiple reactions and multiple glycosidic bonds will result in the formation of a polysaccharide and glycogen, starch and cellulose are recalled and there is a brief introduction to chitin. The final part of the lesson considers how hydrolysis reactions allow polysaccharides and disaccharides to be broken back down into monosaccharides.
This lesson uses step by step guides to describe how to calculate the surface area to volume ratio. The PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons which have been designed to cover the detail of points 8.2 and 8.3 of the Edexcel GCSE Biology & Combined Science specifications.
The calculation of the SA/V ratio can be an area of the course that students find difficult so this lesson breaks the calculation into parts to guide them through each step. The students are shown how to calculate the surface area, then the volume and then how to express the answer of the division calculation as a ratio against 1. After each step, the students are given the opportunity to apply their understanding and all questions have mark schemes with full workings embedded into the PowerPoint to allow the students to self-assess. Students also tend to struggle to see the relevance to Biology so the remainder of the lesson involves the calculation of the ratio for the alveoli in the human body. Students will discover that the surface area to volume ratio is significantly increased in these gas exchange surfaces which leads into the upcoming lesson on the adaptations of the alveoli to overcome the overall low ratio in larger organisms.
This fully-resourced lesson describes how light and electron microscopy can be used to observe cells and cell structures. The engaging PowerPoint and accompanying resources have been designed to cover the content of points 2.1.1 (a) & (f) of the OCR A-level Biology A specification and also describes the difference between magnification and resolution
As this is likely to be one of the very first lessons that students cover in their A-level studies, it’s important to maintain motivation from the off whilst covering the detailed and important content of microscope studies. In line with this, all of the lessons in module 2.1.1 (cell structure) have an ongoing quiz competition where points can be won in rounds that introduced key terms and values. A quiz scoresheet is included within the resources so that the teacher can keep track of the scores over the 7 lessons in the module and the winning team can be revealed at the end of the last lesson.
In this lesson, the quiz rounds are interspersed between a range of tasks which cover the following content:
The use of the light microscope to observe cells
The total magnification as a product of the power of the eyepiece and objective lens
An introduction to the importance of staining
The difference between magnification and resolution
The use of the TEM
The use of the SEM
Due to the detail included in this lesson, it is estimated that it will take in excess of 2 hours of allocated A-level teaching time to cover the content
This lesson describes how molecules move across the cell membrane by the passive methods of simple and facilitated diffusion. The PowerPoint and accompanying resources have been designed to cover the first part of specification point 2.1.5 (d) [i] of the OCR A-level Biology A specification and the factors that increase the rate of diffusion are covered along with the limitations imposed by the phospholipid bilayer and the role of channel and carrier proteins.
The structure and properties of cell membranes were described in the lesson covering 2.1.5 (b), so this lesson has been written to include continual references to the content of that lesson. This enables links to be made between the movement across a cell membrane with the concentration gradient, the parts of the membrane that are involved and any features that may increase the rate at which the molecules move. A series of questions about the alveoli are used to demonstrate how a large surface area, a short diffusion distance and the maintenance of a steep concentration gradient will increase the rate of simple diffusion. One of two quick quiz rounds is then used to introduce temperature and size of molecule as two further factors that can affect simple diffusion. The remainder of the lesson focuses on facilitated diffusion and describes how transmembrane proteins are needed to move small, polar or large molecules from a high concentration to a lower concentration across a partially permeable membrane
This lesson describes the structures and functions of the components of the mammalian gaseous exchange system. The PowerPoint and accompanying resources have been designed to cover point 3.1.1 [c] of the OCR A-level Biology A specification and contains links to future topics such as transport in animals as well as prior knowledge checks of their recall of the content of previously covered modules.
The lesson is filled with a range of activities such as guided discussion periods, exam-style questions (with markschemes) and quiz competitions and these run alongside the slides containing the detailed A-level Biology content to cover the following features:
The incomplete rings of cartilage, ciliated pseudostratified columnar epithelium and goblet cells in the trachea
The narrowing airways of the primary, secondary and tertiary bronchi
The elastic fibres and smooth muscle in the terminal and respiratory bronchioles and the change from simple columnar epithelium to simple cuboidal epithelium
The large surface area to volume ratio and the simple squamous epithelium of the alveoli
The pleural cavity and fluid of the lungs
When describing the production of mucus by the goblet cells in the trachea, time is taken to consider cystic fibrosis and the inheritance of this autosomal recessive disorder. Students will be supported in working out genotypes from a pedigree tree to prepare them for module 6.1.2 (Patterns of inheritance)
This lesson describes the properties of gas exchange surfaces and shows how Fick’s law of diffusion is dependent on these properties. The PowerPoint and accompanying worksheets have been designed to cover points 2.1 (i & ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and there is a particular focus on the relationship between the size of an organism or structure and its surface to volume ratio.
Adolf Fick is briefly introduced at the start of the lesson and the students will learn that his law of diffusion governs the diffusion of a gas across a membrane and is dependent on three properties. The students are likely to know that surface area is one of these properties but although they may have been introduced to the surface area to volume ratio at GCSE, their understanding of its relevance tends to be mixed. Therefore, real life examples are included throughout the lesson that emphasise the importance of this ratio in order to increase the relevance. A lot of students worry about the maths calculations that are associated with this topic so a step by step guide is included at the start of the lesson to walk them through the calculation of the surface area, the volume and then the ratio. Through worked examples and understanding checks, SA/V ratios are calculated for cubes of increasing side length and living organisms of different size. These comparative values will enable the students to conclude that the larger the organism or structure, the lower the surface area to volume ratio. A differentiated task is then used to challenge the students to explain the relationship between the ratio and the metabolic demands of an organism and this leads into the next part of the lesson, where the adaptations of a human to increase the ratio at the gas exchange surface is covered. The students will calculate the SA/V ratio of a human alveolus (using the surface area and volume formulae for a sphere) and will see the significant increase that results from the folding of the membranes. The remainder of the lesson introduces concentration difference and thickness of membrane as the other two properties in Fick’s law of diffusion and students are reminded that the maintenance of a steep concentration gradient and a reduction in the diffusion distance are critical for this transport mechanism.
This lesson has been specifically planned to prepare students for the next lesson which describes how the structure of the mammalian lung is adapted for rapid gas exchange (specification point 2.1 [iii])